a) Field of the Invention The present invention relates to a solid state image pickup device having photoelectric conversion elements and its control method, and more particularly to techniques for controlling charge accumulation times of photoelectric conversion elements.
b) Description of the Related Art
Exposure times (charge accumulation times) of red (R), green (G) and blue (B) pixels of a conventional color solid state image pickup device are controlled uniformly. If an image is picked up under external light having a shifted color temperature, a color balance of the picked-up image becomes poor. For example, if a scene having a high color temperature, i.e., a bluish scene, is taken, although a sufficient signal for B pixels can be obtained, signals for G and R pixels are small. When color image signals having a good white balance are to be obtained from such signals, the dynamic range of the color image is determined basing upon the color signal having the smallest amplitude, in this case, R signal. A reproduced image has a poor color balance in a bright image area, being insufficient for R color and rather having a magenta hue. A reddish scene such as an evening scene has a tendency opposite to that described above.